1. Field of the Invention
The present invention is related to the field of sports boots, and especially to those boots whose upper has an ascending part, such as snowboarding boots, hiking boots and other boots intended for specific sports such as hang gliding, in-line skating or others.
2. Description of Background and Relevant Information
The problem that one faces in tightening boots with ascending uppers derives from the fact that the lower portion or vamp does not require the same tightening as the ascending portion.
Indeed, the lower part generally comprises return elements of the "closed" type, such as loops, guides, eyelets, etc., that form a permanent circuit regardless of the tightening tension, as opposed to return elements of the "open" type for the ascending portion, such as hooks or others, that form a circuit capable of being released as soon as the tightening tension is relaxed sufficiently.
In a permanent type circuit, the friction on the lace is substantial in the area of the return elements. This diminishes the tightening tension in the direction of the end of the boot. The result is a tightening that is not uniform when one pulls at the ends of the lace for the first time. The tightening operation must be followed up by pulling down on those parts of the lace that are inadequately tightened. It is therefore necessary to improve tightening efficiency in this portion whilst minimizing friction, in order to obtain correct tightening, and without having to follow up on the tightening operation.
In order to do this, laces with small sections and little stretching capacity are generally used to improve the sliding, limit the friction and thus encourage tightening. But for an efficient tightening operation, enough tension must be applied on the free ends of the lace. However, the small sections tend to cause a shearing effect in the hands, and this hinders one from applying enough tension in order to efficiently tighten the frontal portion of the upper.
In addition, due to the relative lack of stretching capacity of the lace and its small section, it becomes difficult to obtain a progressive tightening in the raised portion of the upper. Thus, the distribution of the tightening pressures becomes difficult, and often the boot is too tight, thus causing discomfort, or conversely, it is too loose; and in the latter case, there is the risk that the lace will escape from the hooks, especially during bending.
As such, it can be ascertained that to date, there is no lace specifically adapted to sports boots, that enables the tightening operation of the lower part of the upper to be conducted both efficiently and homogeneously in a single movement whilst at the same time providing a good grip. Neither is any lace known that provides efficient tightening for the frontal portion of the upper along with a progressive tightening for the ascending portion of the upper.
Laces comprising portions of different types are known. For example, U.S. Pat. No. 5,074,013 is directed to a traction-resistant lace for at boot, made of a fabric, which includes two free end portions that are covered with strips made of a self-adhering material such as VELCRO. But the object of the invention of U.S. '013 is very specific. Its intention is to provide a connection that resists sliding after being tightened, and thus prevents the lace from becoming undone.